Transcript for Making 'Captain America' Into a Cultural Phenomenon All Over Again

Superheroes. They used to be the domain of common book geeks, but nowadays, hero worship is mainstream and they've got the box office success to prove it. Tonight, nick watt goes behind the scenes with the cast of the new movie "Captain America: The winter soldier." . They save the world, they look great in suits and now they're picking up their power once again. Hey, cap, how do we know the good guys from the bad guys? If they're shooting at you, they're bad. To make money, they need more than superhero geeks to buy tickets. They need comic book ignoramuses like me filing into theatres. That's our burden or challenge every time we set out to make a movie. It has to work on both 4re68s. This is ninth movie marvel has made in its interwoven superhero universe. The avengers plus all the spinoffs. And together they gross nearly $6 billion in the box office in just a few short years. This is a cultural phenomenon of our time. Starring among others, Robert Downey Jr., scarlet Johansson and Samuel L. Jackson of nick fury as the bad ass boss. It's getting damn near time for you to get with that program, cap. Don't hold your breath. Do you ever want to give this up and go play golf? No. Never? I mean, I make money playing golf but I don't make the kind of money playing golf that I do making movies. You make money playing golf? Doesn't everybody? Chris ens is the very same cat that first appeared in comic books back in 1941 as a nazi hunter. In the first captain America film, he was plane old Steve Rogers, a 98-pound weakling. Beefed up by experiments and frozen in the arctic for 730 ye -- 70 years and now he's back. Thor has his hammer. Cap has his sold and nothing else. He's old school. That was part of the appeal of the character. . And Steve Rogers can leap from one car to another car across the freeway and throw the shield and catch it back and can survive a five-story fall landing on his shoulder, but he is at heart the 98-pound weakling that in early 1940s wanted to do his duty and to sign up to help his country the way everybody else was doing. Which is why we can identify with him. Absolutely. It all comes down to the flaw of our heros. The real star is this affable chap in the baseball cap. The president of the studio. If you had a superpower, what would it be? That's ridiculous. Oh, I think invisibility would be good. Then this chair would be empty and you would be talking to nobody, which might be preferable. Reporter: He's a comic book geek who grew up and brought these immechanicals to life for a very wide audience. The movies are phenomenally successful which means the raw material are actually very good. That's the key. People ask what is the secret? My answer is the source material. Read the source material. They are great. Rule number two, costumes matter. Engine room secure. Putting scarlet Johansson in a pair of leather pants. Always a good decision. Number three, aside from scarlet, the movie must look great. And even as a nonconnoisseur, I admit I was excited and grasping at the gritty stunts. It takes a high jacking? Nuclear war would do it, too. Rule number four. It's important, there must be something deeper to reel in the nonaction fans. This film is about more than just the big set pieces and bad guy getting punched in the face. Going to neutralize a lot of threats before they even happen. The Flot revolves around liquidating a threat to seat sometime in the future. Who's actually keeping us safe and how are they keeping us safe. Are the guns turned on us or the enemies. Edward Snowden and his recent revelations of NSA snooping. While we were filming all the Snowden stuff came out and I couldn't believe how applicable it was to the plot we're trying to convey. It's a gray area. Is nick fury a good guy? Yes, he is. He is? Yeah. But, you know, nick is like -- I don't want to say dick Cheney, but he has his idea about how to keep the populous safe. He does what's necessary. certain age go aheaffawing at stuff who went right over my head. So there's a couple of different levels this is working at. Yeah, that's fun. And they're guffaws of recognition. But if they don't over your head, it doesn't matter. It doesn't interrupt the story. Kevin told us the next movie, black widow and captain America get it together. Did he say that? There's no way he said that. You're smarter than I thought you were. Smarter than I look, huh? That's not what I said. That's not what I thought. For night Lynn in los Angeles. Captain America opens in theatres on April 4 and is coming to you from ourparent company Disney.

This transcript has been automatically generated and may not be 100% accurate.

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